# My Calendar I Problem

## Description

LeetCode Problem 729.

You are implementing a program to use as your calendar. We can add a new event if adding the event will not cause a double booking.

A double booking happens when two events have some non-empty intersection (i.e., some moment is common to both events.).

The event can be represented as a pair of integers start and end that represents a booking on the half-open interval [start, end), the range of real numbers x such that start <= x < end.

Implement the MyCalendar class:

• MyCalendar() Initializes the calendar object.
• boolean book(int start, int end) Returns true if the event can be added to the calendar successfully without causing a double booking. Otherwise, return false and do not add the event to the calendar.

Example 1:

``````1
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Input
["MyCalendar", "book", "book", "book"]
[[], [10, 20], [15, 25], [20, 30]]
Output
[null, true, false, true]
Explanation
MyCalendar myCalendar = new MyCalendar();
myCalendar.book(10, 20); // return True
myCalendar.book(15, 25); // return False, It can not be booked because time 15 is already booked by another event.
myCalendar.book(20, 30); // return True, The event can be booked, as the first event takes every time less than 20, but not including 20.
``````

Constraints:

• 0 <= start < end <= 10^9
• At most 1000 calls will be made to book.

## Sample C++ Code

``````1
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class MyCalendar {
private:
vector<pair<int, int>> calendar;

public:
MyCalendar() {}

bool book(int start, int end) {
for (auto [s, e] : calendar)
if (max(s, start) < min(e, end))
return false;

calendar.push_back({start, end});
return true;
}
};

/**
* Your MyCalendar object will be instantiated and called as such:
* MyCalendar* obj = new MyCalendar();
* bool param_1 = obj->book(start,end);
*/
``````